1. Field of the Invention
The present invention relates to integrated circuits, and more particularly to thermal power dissipation of integrated circuits.
2. Description of the Related Art
High temperatures of integrated circuits may decrease reliability and efficiency of the integrated circuit. As the density of transistors on an integrated circuit increases and transistor sizes decrease, thermal power generated by the circuit increases, thus increasing the need for removing heat from a packaged integrated circuit. For example, an increase in transistor density may result in an increase in power density by a factor of two or three.
The thermal resistance of a packaged part typically includes thermal resistance contributions from a lid, a thermal interface material (TIM) between the lid and a backside of an integrated circuit, and the integrated circuit itself. To reduce the overall thermal resistance of the packaged part, one or all of these contributions may be reduced. To improve a thermal resistance of the lid or the TIM, new materials may be used. However, silver or gold alloys which have a low thermal resistance, may be cost prohibitive for the lid of typical integrated circuits. The thickness of the lid may be reduced to reduce the lid's thermal resistance, but elimination of the lid leaves the integrated circuit vulnerable to cracking. Reducing the thermal resistance of the TIM also may be impracticable because although a thermal interface provided by typical TIMs is inferior to thermal interfaces provided by other materials (e.g., some metals or diamond), TIMs are softer than other materials and reduce cracking of the integrated circuit die.
Accordingly, improved techniques for removing heat from a packaged integrated circuit are desired.